Space geodetic science and other disciplines using geodetic products have benefited immensely from open sharing of data and metadata from global and regional archives. The International GNSS Service (IGS) is an example of coordinated sharing of data to enable the production of orbit and other products that benefit nearly all civilian users of GNSS data. Ten years ago, two of the IGS Archive Centers, Scripps Orbit and Permanent Array Center (SOPAC) and the NASA Crustal Dynamics Data Information System (CDDIS) collaborated with UNAVCO to create the GPS Seamless Archive Centers (GSAC) in an effort to further enable research with the expanding collections of GNSS data then becoming available. The GSAC partners share metadata to facilitate data discovery and mining across participating archives and distribution of data to users. This effort was pioneering, but was built on technology that has now been rendered obsolete. As the number of geodetic observing technologies has expanded, the variety of data and data products has grown dramatically, exposing limitations in data product sharing. We propose to expand the original GSAC capability for multiple geodetic observation types and to simultaneously modernize the underlying technology by implementing Web Services at CDDIS, the UNAVCO Data Center, and SOPAC. A science partner

(University of Nevada, Reno) will test these Web Services by incorporating them into their daily GNSS data processing scheme. The effort will include new methods for quality control of current and legacy data that will be a product of the analysis/testing phase performed by UNR. This proposed development will contribute to an improved datum, the International Terrestrial Reference Frame, which is required for the accurate detection and monitoring of sea level change, the distribution of terrestrial water and atmospheric water vapor and other global-change related processes.